1969 Chevrolet - body welding issues

[STEVE POLLARD]

So I have a question regarding my ongoing '69 Impala SS project and I'm looking for another opinion. The paint / body guy ( who has been doing beautiful work for the past 40 plus years ) is concern about the butt-welds on the quarter panels. He believes that once the final body and paint work is done, the butt-welds will show up when the car is out in the sun light. He thinks that I should remove the entire quarter and replace them with NOS quarters. Another company did the body work about 7 or 8 years ago... any thoughts on this ? 

Just a note: the patches were taken from an nos panel from a sedan, so they are not an after-market panel.

 

Steve

 

 

 

Edited May 23 by STEVE POLLARD (see edit history)

[joe_padavano]

Butt welds are the right way to patch sheet metal. Full quarter replacement at the factory seams is an even better solution,  IF you can find full OEM quarters. Crappy fitment and welding will telegraph through the paint, but quality welds and metal finishing will not. Your patches appear to be MIG welds. I prefer TIG and planishing after welding to remove the warpage.

[EmTee]

2 minutes ago, joe_padavano said:

Butt welds are the right way to patch sheet metal. Full quarter replacement at the factory seams is an even better solution,  IF you can find full OEM quarters.

I agree with Joe's assessment of the repair options and your painter's concerns, given the photo seems to show that the weld line isn't completely level with the surface.  The risk is there are micro-perforations in the stitched seam that could allow corrosion.  I'd be somewhat concerned on a car that is driven regularly, regardless of the weather.  On a car like yours, however, that will likely never see a drop of rain, corrosion will probably not be an issue as long as both sides of the panel are properly cleaned, primed and sealed.  The issue with the joint telegraphing through the paint should be able to be addressed through careful bodywork and preparation.  The primers and sealers used should be allowed to fully cure before blocking to ensure there's no additional shrinkage which could allow sanding scratches to reappear.

[Frank DuVal]

TIG, MIG, either will be just fine. We had no TIG in my shop days. 😉 That was specialized commercial stuff.

 

Sure, the old rodder's trick of hammering the welds is great, just hard to do without really long arms in that picture. 🤣  You can do it with MIG since there are auto darkening helmets so you can see to pick up the hammer and dolly quick. Same skip weld technique is required with either MIG, TIG or torch. Hot metal moves.

 

You do need a continuous weld bead when finished (not while welding!), and the ability to treat both sides of the finished weld.

 

Of course, the welding is finished, 7 or 8 years ago... so just check for porosity/holes and if any, those holes need to be cleaned before priming/sealing.

 

My personal favorite is two part epoxy primer. You work the filler (yeah, try to weld without needing some filler 😉) over the epoxy primered area with most brands, check the label.

 

Is he worried about seeing the weld area in the bright sunlight (if so, it needed proper filling to make the area smooth), or the sunlight heating the repair and causing shrinking of the filler/paint to where the repair is visible (if so, the filler needs to dry to complete cure before paint is applied so no more shrink from evaporation happens, and same for primer layer, complete cure so no more evaporation happens). 

 

So, the thousand dollar question, if you put a factory quarter on, there is still a weld area that needs filling. Why is he not concerned with that area? Going to cover it with a vinyl roof?

[joe_padavano]

18 minutes ago, Frank DuVal said:

So, the thousand dollar question, if you put a factory quarter on, there is still a weld area that needs filling. Why is he not concerned with that area? Going to cover it with a vinyl roof?

The factory seam at the C-pillar is designed to be spot welded then leaded. All the other seams are not exposed (in the trunk gutter or at the door jamb). Of course, this requires one to source a full quarter and not the repro partial quarters that still require a butt weld.

[STEVE POLLARD]

37 minutes ago, Frank DuVal said:

So, the thousand dollar question, if you put a factory quarter on, there is still a weld area that needs filling. Why is he not concerned with that area? Going to cover it with a vinyl roof?

[28 Chrysler]

If the welds are good and are fairly ground level it should work out fine with the light green paint.

I you are going for a show car you better check the other side, it looks like a rust repair.

 

[joe_padavano]

1 hour ago, STEVE POLLARD said:

From above:

 

1 hour ago, joe_padavano said:

The factory seam at the C-pillar is designed to be spot welded then leaded. All the other seams are not exposed (in the trunk gutter or at the door jamb). Of course, this requires one to source a full quarter and not the repro partial quarters that still require a butt weld.

 

The factory C-pillar and rocker panel joints are recessed so they can be spot welded on the assembly line then filled with lead. All the other joints are lap joints (such as in the trunk gutter) or pinchweld joints (at the bottom of the fender and under the windlace at the door opening). Correct installation means melting out the old lead, getting it completely removed from the remaining metal so the welds can be made, then re-applying lead.

 

Obviously this is a Camaro, but the basic concept is the same. The seam at the top of the c-pillar is recessed. Once spot welded it is filled with lead. The Trunk gutter and bottom of the fender to trunk dropoff and joint at the door opening are all lap joints that are hidden by trim or weatherstripping or are on the underside of the car.

 

 

 

[Rusty_OToole]

2 questions. How much will it cost and is it worth it? I am sure we are talking many thousands of dollars and if it was mine, I would not spend that much to avoid a nothing problem. Even if the seam shows in strong sunlight so what?

[Frank DuVal]

13 hours ago, joe_padavano said:

The factory seam at the C-pillar is designed to be spot welded then leaded.

Yep, that's the one I'm talking about. It was leaded in 1969. That's 99% not happening today. Heck, even Ford and Chrysler had abandoned lead on the C pillar by the early 70s and used plastic filler. So what would this body shop do about this seam when he puts on a full quarter that would be so different than what he is so upset about the lower butt welded seam?❓

 

I call "I won't guarantee it because I did not do it" on the lower butt welded seam. He's right then, he should not guarantee other's work.

 

And, LEAD MOVES TOO! I've seen many a leaded seam showing under the paint.😮 And not from rust, but simple movement of the lead, enough to show.

Edited May 24 by Frank DuVal (see edit history)

[EmTee]

7 hours ago, Frank DuVal said:

And, LEAD MOVES TOO! I've seen many a leaded seam showing under the paint.😮 And not from rust, but simple movement of the lead, enough to show.

True, however, I think the point Joe is making is that if the C-pillar joint is visible under certain conditions at least that would be consistent with the way the car was originally designed and built.  I have seen original cars where the C-pillar joint is visible in the right (er, 'wrong') light.

 

That said, if it were my car, I would likely judge the risk/reward ratio low enough to not justify the expense of a full quarter panel replacement.  But, that means nothing if every time Steve looks at his car his eyes focus on that lower left quarter panel...

[Ben Bruce aka First Born]

Much ado about nothing, me thinks.

 

  Ben

[joe_padavano]

Leading is not "99% not going to happen" today. I have lead-free body solder. Eastwood (among others) sell this. The problem is removing the old lead. And no, don't expect 99% of the body shops to know how to do this or to use these products, which is why I do it myself.

[ABear]

13 hours ago, Frank DuVal said:

Heck, even Ford and Chrysler had abandoned lead on the C pillar by the early 70s and used plastic filler.

NOPE. Not sure about Chrysler, but FORD was still using lead up to and including at least the 1980s and perhaps into the 1990s..

 

I have 1973 and 1976 Fords and EVERY seam is 100% leaded with zero plastic filler.

 

13 hours ago, Frank DuVal said:

And, LEAD MOVES TOO! I've seen many a leaded seam showing under the paint.😮 And not from rust, but simple movement of the lead, enough to show.

Lead "movement" as far, far, far, far less than ANY plastic/resin/fiberglass fillers which have a very large expansion/contraction ratio compared to the steel that it is applied to. It is far rarer to "see" a good quality leaded joint "show" than plastic fillers where there is large temperature swings.

 

For example..

 

6 PPM mild steel

10 to 16 PPM solder (various lead percentages from Babbit to 50/50)

25-75 PPM for plastic resin fillers

 

Want to take a guess at which "filler" is more "compatible" with steel expansion/contraction ratio?

 

It ISN'T plastic body fillers..

 

Plastic fillers are the cheap and easy "body mans" way out of which is why it is commonly used by handiman backyard shade tree repairers and even "professional" body shops. Takes zero knowledge to plaster a bunch of filler on then grind and sand it down..

 

Leading takes more finesse, time and knowledge but when done correctly can and will outlast the rest of the car body..

 

Plastic fillers, yeah, I have seen many of those repairs pop out and rust under the filler..

 

Makes me cringe everytime I watch any of those made for TV car shows that show their bodymen slathering layer on layer of plastic resin filler which they are blocking the body..

 

And by the way, plastic resin fillers attract and hold MOISTURE from the air, applying plastic fillers directly to raw steel is a built in rust rot time machine.. The plastic filler traps and holds moisture and when you add a layer of paint over top of the resin you have just sealed that moisture under the paint.. It has no place to go but to attack the steel it is attached to..

 

Bodyshops won't do leading today due to the regulations on lead hazards and it can be a bit more time/labor intensive..

[ABear]

On 5/23/2024 at 10:47 AM, Frank DuVal said:

You do need a continuous weld bead when finished (not while welding!), and the ability to treat both sides of the finished weld.

NOPE.

 

The is a recipe for severe warpage.

 

STITCH/SKIP welding reduces the chance for warping.

 

My Dad used to use Oxy/AC torch with coat hanger and could stitch a weld in so nice with nearly no warping..

 

The key to not warping is minimizing the amount of heat, a continuous weld keeps adding more and more heat and that requires a lot of after weld work trying to shrink/expand with hammer and dolly.

 

MIG welder is perfect for stitching, quick, short bursts (little "dots"), then move several inches then do over. Work from the middle of panel towards ends of panel. Once you reach the ends, you start in the middle again and fill in between each previous stitch, repeat until each stitch is tied together.. Grind down excess taking care that you do not stay in one place to overheat the metal. Then come back and stitch any holes that were found after grinding.. The grind down again until the welds are flash with parent metal..

 

In the OPs case, the welds look OK, if it was my car, I would simply grind any welds that may be above the parent metal until they are flush. Then I would add some leading over the weld and then shave the leading down to flush with the parent metal.. When done correctly, the need for slathering on layers of plastic filler would not be needed.

 

On edit..

 

For those who disagree, I am including some pictures..

 

First picture is after I stitch welded the panel and had ground down all of the welds flush to parent metal.

 

Second picture is after I leaded the seam and applied very light coat of primer to prevent the panel from rusting while working elsewhere on the car.

 

That panel welded in perfect with no warpage just by using the method I outlined above.

 

One caveat, the welder I use is a Miller Autoset MIG, I set it to the thickness of the metals I am working with and it automatically regulates wire speed and current. This way I do not have to fuss with the settings.

Edited May 24 by ABear (see edit history)

[joe_padavano]

1 hour ago, ABear said:

NOPE.

 

The is a recipe for severe warpage.

 

STITCH/SKIP welding reduces the chance for warping.

 

My Dad used to use Oxy/AC torch with coat hanger and could stitch a weld in so nice with nearly no warping..

 

The key to not warping is minimizing the amount of heat, a continuous weld keeps adding more and more heat and that requires a lot of after weld work trying to shrink/expand with hammer and dolly.

There are misconceptions here. First, the prior comment about continuous welding was NOT meant to infer a single continuous weld but a weld where through skip welding, the seam ended up as a continuous weld (as opposed to the tacks that had open gaps between them as seen in the photo in the first post in this thread). As for heat being the recipe for warpage, the truth is more complex. It isn't heat expansion that causes the warping and oilcanning, it's the shrinkage. The weld (no matter how long) solidifies when the metal is just below the melting temp and thus still expanded. As this solidified joint cools to room temp, the metal shrinks, which is what causes the warpage. The best metalfinishers will planish the weld to stretch it back to the original shape, reversing the shrinkage. MIG welds are harder and thus less able to be planished. TIG and gas welding is much more accommodating to planishing, which is why all the high-end metalworking shops use TIG. MIG has it's place in locations where it is impossible to reach the backside for planishing (like sectioning rockers), but for quality work, use TIG. Unfortunately, this process is much more time consuming than simply tacking with MIG and slathering on bondo, which is what most people do.

[ABear]

6 minutes ago, joe_padavano said:

TIG and gas welding is much more accommodating to planishing, which is why all the high-end metalworking shops use TIG. MIG has it's place in locations where it is impossible to reach the backside for planishing (like sectioning rockers), but for quality work, use TIG.

I don't have a TIG machine, cost wasn't in the cards for that.

 

MIG can be done with no or minimal warpage, I have done it. Yes, MIG wire is harder than the parent metal, but as long as one learns how to control the amount of wire used the grinding is minimal. Can't just bird poo it on and expect results, takes a good eye/hand control and coordination.

 

10 minutes ago, joe_padavano said:

There are misconceptions here. First, the prior comment about continuous welding was NOT meant to infer a single continuous weld but a weld where through skip welding, the seam ended up as a continuous weld

With any weld, heat control trumps everything, if it turns red and stays red, it is too hot. That is where you can use little tack welds which look like little dots when done correctly. A good MIG welder properly setup really shines here on this aspect as you can quickly pull the trigger and let up as fast as you pulled the trigger, the resulting dot is red for a second and cools quickly. You cannot do that with TIG as TIG is more like OXY/AC only instead of burning gasses and filler rods you are using electric arc and hand filler rods.

 

The downside of MIG getting every pin hole welded.. That is where TIG shines, but heat control with TIG is not as easy as a properly setup MIG welder so with TIG you WILL have to go back and stretch/shrink.

 

The panel I did in the pictures I posted have zero, yes, zero warps, I was actually shocked as I was expecting to have to do some hammer and dolly work.

 

In the end, I only had to do a very little narrow bead of leading, the leading when done correctly will seal all of any pin holes (the tin/lead solder is drawn into the pin holes) I may have missed welding closed. Leading is a bit of a misnomer, in reality it is basic soldering skill with a twist of once the lead is on, you only add just enough heat to make it sort of putty like consistency which you can move around with maple wood tools (tool surface you coat with beeswax). After the leading cools, you come back over with files and file excess leading flush with parent metal.

 

I found this to be much easier for me than messing around with plastic fillers and over the yrs I have seen lots of plastic fillers that failed.. Really stinks to spend a lot of time making nice repairs then in a few yrs to have that nice paint job with those repairs pop out all rusted.. Living in the rust belt I have learned that the cheap and easy way with plastic fillers is not worth my time.

[Frank DuVal]

7 hours ago, ABear said:

On 5/23/2024 at 10:47 AM, Frank DuVal said:

You do need a continuous weld bead when finished (not while welding!), and the ability to treat both sides of the finished weld.

NOPE.

 

The is a recipe for severe warpage.

 

That's what I SAID! "When finished" is just that, at the end of the repair time. Could be a few days, weeks...🤣

 

5 hours ago, ABear said:

Living in the rust belt I have learned that the cheap and easy way with plastic fillers is not worth my time.

If you do it right, this is not an issue. Of course right is not the cheap and easy way even with plastic fillers. Remember, paint is a plastic filler.... Right is NO unprepped metal. Rusting out because of ingested salt in the pinchwelds is the issue with northern salt belt cars....  We live on the edge of salt, some years in the middle of it (brine...🤬).

 

8 hours ago, ABear said:

For example..

 

6 PPM mild steel

10 to 16 PPM solder (various lead percentages from Babbit to 50/50)

25-75 PPM for plastic resin fillers

See, you prove it moves! Now we can talk different rates, but it still moves. Most people insist on lead thinking it does not move.

 

 

Now, the thousand dollar question, or million dollar question. Why did the car companies stick with lead so long for seam leveling? Plastic fillers were out in the 50s. Hint, it wasn't because it was cheaper to buy than plastic.

 

 

Oh, and I worked on Fords from the mid 70s that had plastic filler in the C pillars and at the A pillars. But not all, I did strip a roof on a Mavrick that was leaded at the posts. So maybe different plants....😉

[STEVE POLLARD]

On 5/24/2024 at 2:29 PM, ABear said:

In the OPs case, the welds look OK, if it was my car, I would simply grind any welds that may be above the parent metal until they are flush. Then I would add some leading over the weld and then shave the leading down to flush with the parent metal.. When done correctly, the need for slathering on layers of plastic filler would not be needed.

Thanks for all the input.... great information here ! I think I want to look into the leading process a little more once I get back on tract with the restoration.

[Rusty_OToole]

One reason for using lead fill on an assembly line is that it hardens immediately. You don't have to wait 20 minutes to sand it as you would with plastic fill.

[EmTee]

It would also seal any tiny interruptions (gaps) in the butt-weld seam.  This would seem to be a good alternative to full replacement.

[Frank DuVal]

Yes, Rusty, that is the correct answer! It was faster on the assembly line to lead the seam and the next worker cut it down to prepare for priming. Plastic filler took too long for the way the line was set up. Of course, "they" finally changed to modern methods and plastic filler. Many changes in processes since then!👍

[kramaton]

Why not a coating of lead to seal it then finish it with modern filler?

[R Walling]

This post reminded me of the first qut. panel that i seen being installed.

 He pop rivited  a used qut. over the complete dented qut. and filled it with bondo.

 Because he didn't trim off the lower edge of either qut., it was impossible to remove the tire!

 

 Ps,  The next time that I seen him, several years later, he was an insurance appraiser telling me how to repair a car!

[ABear]

On 5/28/2024 at 11:12 AM, kramaton said:

Why not a coating of lead to seal it then finish it with modern filler?

Good question, I am sure some of the experts would disagree with this idea, there seems to be in the autobody world a "rift" between all leading and all modern plastic filler.. Seems for the most part most people go with strictly all plastic.. I am not a fan of all plastic, have seen way to many times failure of the paint or rustouts under the filler.

 

There is nothing to stop you from using leading to make your major adjustments and plastic filler for final finished surface, it can be done. I actually think a combination might work much better than all plastic filler.

 

Factory used leading for many reasons, it was quick, no wait times for plastic filler to harden, plentiful and cheap, easy to work and rework and adjust even after it is applied (try that with plastic fillers).

 

The downside to leading today is lead has been banned to death out of everything, I still have some actual real leading sticks to work with, but it is getting harder to get them as the no lead substitutes are pretty much what is sold now days.. No lead versions however have a higher working temperature which gets you close to creating warps that you don't want.

 

Doubt you will find autobody shops that will even consider using leading, it is a dying "art" so to speak, most bodymen now days do not have the proper understanding and skills.

 

Myself, leading properly done should not need any plastic fillers.

 

When done right, the entire repair will disappear with leading only..

 

There is some really good videos that go over how to body lead..

 

HERE IS ONE

 

They use a Oxy/ac torch, I use a propane pencil tip torch for small areas and for larger areas I use a normal propane torch, Oxy/ac is preferred. I do have Oxy/ac but getting tanks refilled is a hassle.

 

 

 

 

[ABear]

On 5/24/2024 at 3:49 PM, joe_padavano said:

There are misconceptions here. First, the prior comment about continuous welding was NOT meant to infer a single continuous weld but a weld where through skip welding, the seam ended up as a continuous weld (as opposed to the tacks that had open gaps between them as seen in the photo in the first post in this thread). As for heat being the recipe for warpage, the truth is more complex. It isn't heat expansion that causes the warping and oilcanning, it's the shrinkage. The weld (no matter how long) solidifies when the metal is just below the melting temp and thus still expanded. As this solidified joint cools to room temp, the metal shrinks, which is what causes the warpage. The best metalfinishers will planish the weld to stretch it back to the original shape, reversing the shrinkage. MIG welds are harder and thus less able to be planished. TIG and gas welding is much more accommodating to planishing, which is why all the high-end metalworking shops use TIG. MIG has it's place in locations where it is impossible to reach the backside for planishing (like sectioning rockers), but for quality work, use TIG. Unfortunately, this process is much more time consuming than simply tacking with MIG and slathering on bondo, which is what most people do.

After thinking on this for a while, technically if you draw a bead longer than a "dot" or "spot weld" you ARE creating a "continuous weld" even if you "skip" and leave a gap. The longer you weld, the more heat buildup in the adjacent sheet metal and thin sheet metal does not do a very good job of dissipating the heat. The thinner the metal the shorter your weld bead must become.

 

This is an inherent problem with ANY welding whether it is TIG/MIG/OXY/AC/Stick.

 

The trick to welding thin sheet metal comes down to how well you DON'T add heat.

 

The longer of the weld you make, the more heat buildup you get.

 

Short bursts of weld are more "ideal" than running a short weld bead, basically you create small "dots" and those dot's and surrounding sheet metal dissipate the heat very quickly, much faster and less metal affected by heat.

 

Creating small weld beads just isn't were TIG does well. You have to strike the arc, insert the cold filler rod into the stream then remove filler and turn off the arc as fast as you can. Sure you could make small short welds but not so much as a "dot".

 

Additionally to help with heat control, whenever I butt weld, I use a "backer", a backer is nothing more than a temporary and removable piece of metal on the backside of the weld. Backer tools are typically something that steel rod will not weld to like copper or aluminum. They do make and sell backer tools, but I make my own out of some copper flashing I have laying around and I added several strong magnets to hold the backer in place. Do have to be careful of magnets close to your welding as it can affect the travel of your filler..

 

If you want a very smooth surface on the outside of the panel that doesn't need much grinding, you can weld from inside to the outside placing the backer on the outside of the panel..

 

There are lots of tricks over the years I have figured out, but I get it, many of "old dogs" are on this forum that don't like change or new ideas.. Fought that battle with my Dad for yrs as he was old school Oxy/AC for everything.

 

I am including a drawing that may be helpful for those looking at tackling welding sheet metal comparing conventional skip weld to my modified version.

[ABear]

On 5/24/2024 at 10:48 PM, Frank DuVal said:

See, you prove it moves! Now we can talk different rates, but it still moves. Most people insist on lead thinking it does not move.

Need to address this a bit.

 

No, I didn't prove it moves, in reality EVERYTHING moves.

 

Instead I proved HOW LITTLE it moves compared to plastic fillers.

 

This is a very important point, as everything "moves" it is just they move at different rates and different amounts.

 

Sheet metal moves, your primer and paint moves but yet they stay in place unless there is something between the sheet metal and paint that that has an extreme amount of expansion and contraction..

 

My "point" is that LEADING has a much more compatible to steel expansion/contraction ratio, therefore the overall stability is much better with LEADING than with plastic fillers. Basically Leading and steel are close enough to the same expansion/contraction ratio that it does not move enough to cause paint issues. When you have close compatibility you have a much more stable platform for your paint to reside on.

 

Leading does also has some elasticity that plastic fillers do not have at cooler temperatures and that means if one were to bump the repaired area you have a far better chance that the lead/paint will not break loose from the steel under it..

 

Plastics have an inherent weakness with cold temperatures, it gets brittle when exposed to cold, cracks easily in cold which leads to breakouts and bubbling of your paint over time and exposure to large temperature swings.

 

I only consider using only plastic fillers for projects I don't give a darn about, not concerned about longevity or not planning to hold on to long term..

 

If you "value" your hard work and all that time you put into your projects and don't wish to repeat repair the same repair in 5-15 yrs you might wish to reconsider slathering the backyard mechanics plastic silly putty on everything.. Yeah, plastic filler stuff can be made to look like multi-million dollars Mecham auction beauty queens but under that facade is hiding a ticking time bomb..

 

Living in the rust belt, the truth will eventually be exposed..